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The synthesis and isolation of [Ru(Cp)(PCy2NPh2)(=C=CHPh]PF6 and [Ru(Cp*)(PCy2NCy2)(=C=CHPh)]PF6 was successfully accomplished. Use of these ruthenium vinylidene complexes for stoichiometric reactions with a variety of amines was performed. Upon reaction with alkyl amines, deprotonation of the Cβ hydrogen resulted in formation of acetylide complex [Ru(Cp*)(PCy2NPh2)(−C≡CPh)], and the species was confirmed through independent synthesis. In contrast, reaction of the less basic aryl amine aniline with [Ru(Cp)(PCy2NCy2)(=C=CHPh)]PF6 resulted in outer sphere addition to give a Fischer carbene product. [ABSTRACT FROM AUTHOR]

Abstract: A family of [CpRu(PP)(MeCN)]PF6 complexes (2 a–e and 4) were prepared in which the bis‐phosphine ligand contains a pendent tertiary amine in the second‐coordination sphere. 2 a–e contain PPh2NR′2 ligands with two amine groups as the pendent base. Complex 4 has the PPh2NPh1 ligand with only one pendent amine. The catalytic performance of 2 a–e and 4 were assessed in the cyclization of 2‐ethynyl aniline and 2‐ethynylbenzyl alcohol. It was revealed that the positioning of the pendent amine near the metal active site is essential for high catalyst performance. A comparison of PPh2NR′2 catalysts (2 a–e) showed minimal difference in performance as a function of pendent amine basicity. Rather, only a threshold basicity – in which the pendent amine was more basic than the substrate – was required for high performance. [ABSTRACT FROM AUTHOR]